Accelerator of vulcanization



mg together the reactants in' an inert solvent Patented Aug. 4, 1936ACCELERATOR F VULCANI'ZATIO'N Lorin B; Sebrell, Silver Lake, 0hio,assignor, by mesne assignments, to Wingfoot Corporation,Wilmington,'Del., a corporation of Delaware No Drawing. Application June8, 1934, Serial No. 729,697. In Canada November 5, 1932 17 Claims. (01.1s 53') My invention relates to a classof compounds, new in and ofthemselves, which'have been found to be excellent acceleratorsdf'the'vulcaniz'ation of rubber. More particularly it concerns that classof accelerators known as substituted ammonium salts of mercaptothiaz'oles. I have-discovered a new class of these salts; namely thealicyclic ammonium thiazyl sulphides, which may also be called cycloparafilnic hydrocarbon amprirnary alicyclic amines such as cyclohexylamine, ortho methyl cyclohexyl amine, p-methyl: cyclohexylaminejhexrhydro xylidine, 4-phenyl l-amino cyclo hexane, p-ethoxycyclohexyl am ine, o-ethoxy cyclohexyl amine,,m-methoxy cy- 5 clohexylamine, o-methoxy clyclohexyl amine, p-methoxy cyclohexyl amine,hexahydro p-amino dimethyl aniline and 1.-amino 4-hydroxy cyclo hexane.Others are alicyclic tetra hydro beta monium thiaz l sul hides: orsaturatedisoc clic ammonium thi azyl'gulphides. 'I'hes' compo ndsnaphthylamme ahcychc tetra hydro alpha naph' may be prepared by theSimple expedient of thylamine, aryl tetra hydro beta naphthylamine,fluxing substantially molar quantities of the de r l tetra hydro alphanaphthylamm? the sired alicyclic amine withja' suspension of the ahrdronaphthylammes bornyl m desired mercapto'thiazole in an inert'solvent foramme Examples of secondaryahcychc ines which will react, with themerc'aptothiazoles are methyl cyclohexyl amine, ethyl cyclohexyl amine,dicyclohexyl amine, benz yl cyclohexyl amine, V cyclohexyl aniline,N-methyl tetra hydro alpha orbeta ,naphthylamine, .Neethyl beta deca-12O hydro naphthylamine, cyclohexyl isopropyl amine, cyclohexyl butylamine, ,andthe like. .Tertiary. amines such astricyclohexyl amine mayalsowbe employed but it will usually be found rather diflia suitableperiod, generally about an hour. These materials may also be prepared bysimply bringat normal room temperatures. I v

The following are illustrative examples of mercapto thiazoles which maybe employed; Z -men captobenzothiazole, 2-mercapto 4=phenyl thiazol e',I G-methyl meroaptobe'ri'zdthiazole, 55 or fi-chlor'omercaptobenzothiazole, B ami'no mercaptobenzo-- thiazole, 5- or G-nitromercaptobenzothiazole, 5- chlor 6-nitro mercaptobenz'othiazola' l methylmercaptobenzothiazole, 2 mercapto naphtha thiazole, 2-mercapto 4-phenylben'zothiazole, 2-mercaptothiazole, 2-mercapto 4-methyl'thiazole, 2-

In the reaction of these alicyclic amines with the mercaptothiaz oles,the nitrogen atornofthe amino group is apparently added' 'directlv' tothe sulphur in'the mercapto group. For example, the

mercapto xylyl thiazole, 2-mercapto '5 -metho'xy reaction of ethylcyclohexyl amine with mercapbenzothiazole, Z-mercapto 5-ethoxyben'zothiatobe'nz'othi'azole is believed to be represented thus:

' 02H; 1 s 9 11, ig-a -s Hz C-SH+H-N C-S-N p HQ? 3 v H H2 I i H2 H2zole, and otherhalogen-Q nit1"0, 'hydroxy-, al- That between methylcyclohexyl amine and 6-, koxy-, and amino-substituted arylene mercaptoamino:mercaptobenzothiazole may be expressed thiazoles. as follows: 40

HaN s 011: 7 CH3 c+s-H+H-N H2 11H Hm :s

N CSN H2 N/ f Ha H2 11/ H 2 Examples of 'alicyclic amines reactivewiththe That between cyclohexyl amine and merca'pL. mercapto thiazoleshereinbefor'e set forth are the tobenzothiazole may be expressed asfollows:

v H2 H2 S V H2 Ht- S fi H osH+i1 H Hm HI /N av cult to isolate thereaction product.

The compounds in question may be prepared by the refluxing of the aminein a suspension of the mercapto aromatic thiazole in an inert solvent.The crude products, although of high purity, may be further purified byrecrystallization from alcohol. As a specific illustration, ethylcyclohexyl ammonium benzothiazyl mono sulphide is prepared by refluxing1 mol of ethyl cyclohexyl amine with a suspension of 1 mol ofmercaptobenzothiazole in high test gasoline for a period of one hour.The resulting product when recrystallized from alcohol has a meltingpoint of 133 degrees C. and an analysis of nitrogen 8.95% and sulphur22.05%. The calculated theoretical analysis for ethyl cyclohexylammonium benzothiazyl mono sulphide is nitrogen 9.52% and sulphur21.78%.

Dicyclohexyl ammonium benzothiazyl mono. sulphide is prepared similarlyand is a crystalline compound having a melting point of 172 degrees C.and an analysis of nitrogen 7.83% and sulphur 18.65%. The calculatedvalues for the percentages of nitrogen and sulphur in dicyclohexylammonium benzothiazyl mono sulphide are 8.05 and 18.39 respectively.

In the case of cyclohexyl ammonium benzothiazyl mono sulphideapproximately 1 mol of cyclohexyl amine is added to an alcoholicsolution of 1 mol of mercaptobenzothiazole at normal room temperature.The product separates as white crystals having a melting point of155-157 degrees C.

Although the compounds may be employed in most of the standard rubberformulae, the following is an example of one in which they have beenfound to be effective as accelerators:

Parts Rubber 100.00 Zinc oxide 5.00 Sulphur 3.00 Stearic acid 1.50Accelerator 0.50

To test the value of these new materials as accelerators, two sets ofsamples prepared in accordance with the above formula were subjected tovulcanization for varying periods of time. One set of samples was testedfor elasticity and tensile strength immediately, while the other set wasweighed, aged in an oxygen bomb for six days at a temperature of 50degrees C. and at a pressure of 150 pounds per square inch, andreweighed in order to ascertain the increase in weight due to absorptionof oxygen prior to its testing for elasticity and tensile strength. Theresults of these tests are shown by the following data:

Load in kgs/cm I at Time of cure llercent Percent in mine. at e ong. atweig 1: 260 F. 5 3 Break break increase Dicgclohezgl ammoniumbenzothiazyl mono sulphide Original Aged in oxygen bomb Ethylcyclolierul ammonium benzothiazyl mono sulphide From this it will beseen that the compounds are powerful accelerators of vulcanization,giving rubber articles of increased tensile strength and elasticity. Itis also noted that they give rubber stocks with excellent ageingqualities. Further they are substantially non-toxic, may be readilyincorporated in rubber and are quite simply prepared. It is apparentthat a new group of highly valuable compounds has been discovered.

This application is in part a continuation of application Serial No.596,145, filed March 1, 1932.

It will be understood that the details of the invention may be variedWithin comparatively wide limits without departing from the inventiveconcept and that it is therefore desired to embrace within the scope ofthe invention such modifications and changes as may be necessary toadapt it to varying conditions and uses. It is intended that the patentshall cover, by suitable expression in the appended claims, whateverfeatures of patentable novelty reside in the invention.

What I claim is:

1. The process of treating rubber which comprises subjecting it tovulcanization in the presence of N-cyclohexyl ammonium benzothiazyl monosulphide.

2. The process of treating rubber which comprises subjecting it tovulcanization in the presence of an N-cyclohexyl ammonium benzothiazylmono sulphide.

3. The process of treating rubber which cornprises subjecting it tovulcanization in the presence of an N-cyclohexyl ammonium benzothiazylsulphide.

4. The process of treating rubber which comprises subjecting it tovulcanization in the presence of a primary alicyclic ammonium benzothiazyl mono sulphide.

5. The process of treating rubber which comprises subjecting it tovulcanization in the presence of an alicyclic ammonium benzothiazyl monosulphide.

6. The process of treating rubber which comprises subjecting it tovulcanization in the presence of an alicyclic ammonium aromatic thiazylsulphide.

7. The process of treating rubber which comprises subjecting it tovulcanization in the presence of a primary alicyclic ammonium aromaticthiazyl mono sulphide.

The process of treating rubber which comprises sub ecting it tovulcanization in the presence of an N-cyclohez'ryl ammonium aromaticthiazyl mono sulphide.

9. The process of treating rubber which comprises subjecting it tovulcanization in the presence of N-cyclohexyl ammonium aromatic thiazylmono sulphide.

10. The process of treating rubber which comprises subjecting it tovulcanization in the presence of an ammonia addition product of amercapto aromatic thiazole, the ammonia additament being substituted byat least one radical containing an alicyclic group.

11. The process of treating rubber which comprises subjecting it tovulcanization in the presence of a oycloparaflinic hydrocarbon ammoniumthiazyl sulphide.

12. The process of treating rubber which comprises subjecting it tovulcanization in the presence of an ammonium benzothiazyl sulphide, the

ammonium group being substituted by a cyclic group containing at leastone alicyclic group.

13. The process for treating rubber which comprises subjecting it tovulcanization in the presence of a primary cyclohexyl ammoniumbenzothiazyl sulphide.

14. A rubber product which has been vulcanized in the presence ofN-cyclohexyl ammonium benzothiazyl sulphide.

15. A rubber product which has been vulcanized in the presence of aprimary cyolohexyl ammonium benzothiazyl mono sulphide.

16. A rubber product which has been vulcanized in the presence of aprimary alicycic ammonium aromatic thiazyl sulphide.

17. A rubber product which has been vulcanized in the presence of analicyclic ammonium aromatic thiazyl sulphide.

LORIN B. SEBRELL.

